1. Field
Example embodiments relate to wireless serial bus networks, and more particularly to a method and system for managing power in wireless universal serial bus networks.
2. Description of Related Art
Due to increases in the use of Universal Serial Bus (USB) in communication devices, Wireless USB (WUSB) networks are becoming increasingly popular. WUSB networks are also referred to Certified WUSB (CWUSB). WUSB networks enable communication devices to communicate with each other in, for example, a range of a few meters. Examples of these utilized communication devices include: personal computers, laptops, personal digital assistants, mobile phones, and other similar devices.
CWUSB devices may be in three modes. For example, the CWUSB devices may be in ‘switched off mode’ (or disconnected mode), in ‘sleep mode’, or in ‘awake mode’ (also referred to as ‘active mode’). In ‘switched off mode’, the WUSB device is switched off. In the ‘disconnected mode’, the WUSB device is not connected to the WUSB network. Further, in ‘active mode’, active CWUSB devices may track all Micro Management Controls (MMCs) scheduled by a CWUSB host. Tracking all MMCs helps the active CWUSB devices check if any transactions are scheduled to the active CWUSB devices. Furthermore, an MMC is a protocol used by which a CWUSB host manages CWUSB device clusters.
CWUSB devices that are in ‘sleep mode’ wake up at various intervals and send either a DN_Alive notification (to the WUSB host) to transit to an awake state unconditionally or a DN_Sleep notification (to the WUSB host) to check if any work is pending with the CWUSB host. The intervals may be irregular and may be set by a vendor.
A CWUSB device may use a Device Notification Time Slot (DNTS) to send asynchronous notifications to the CWUSB host. According to existing techniques, a DNTS scheduling in MMCs by the CWUSB host is arbitrary. For example, a CWUSB device uses DNTSs to transit from ‘sleep mode’ to ‘awake mode’ or to check if any work is pending with the CWUSB host.
Generation rate of MMCs causes a great amount power consumption in CWUSB devices. As such, a CWUSB device in ‘awake mode’ needs to keep all hardware and/or software peripherals in the highest power mode so that the CWUSB device may immediately process any transactions that come in any MMC. Also, sending a DN_Sleep notification, to check if any work is pending with the CWUSB host, results in higher protocol and system overhead. In addition, to check if any work is pending with the host, a CWUSB device needs to place both hardware and software in high power mode and perform a protocol operation (resulting in further overhead). Moreover, scheduling a DNTS in MMCs by the CWUSB host requires CWUSB devices to track each MMC to detect a DNTS and to then transmit. As detection of DNTS is non-deterministic, the DNTS tends to waste device power.
In light of the above discussion, there is a need for a method and system to efficiently manage power in wireless universal serial bus networks.